There is a burgeoning use of vehicles, particularly recreational vehicles, in which the rider as well as the grip surfaces, for example operator grip surfaces used to control operation of the vehicles, are exposed to the elements. Such vehicles include, for example, snowmobiles, snow throwers, all-terrain vehicles (ATV's), motorcycles, etc. Grip surfaces include, for example, sets of handlebars, hand grips, combinations of handlebars and hand grips, etc.
One problem with such a vehicle, particularly when the vehicle is used in cold weather, is that a rider's hands can get very cold during operation of the vehicle since both the hands and the grip surface are exposed to the elements. To mitigate against this problem, the vehicle may be manufactured having a heating element, for example a resistive heating element such as heater coils, embedded in or mounted on the grip surface to warm the grip surface and the hands during operation of the vehicle.
However, control of the heating element to provide maximum comfort and safety while reducing power consumption continues to be a problem in the art. For example, current hand grip heating systems for snowmobiles require constant adjustment of the temperature setting as environmental conditions change (e.g. wind chill factor, ambient air temperature, amount of sunlight, body temperature of the rider, etc.). Since environmental conditions can change quite rapidly, an operator must adjust the temperature setting often, leading to distractions as well as to inefficiencies in temperature control. Such distractions increase the likelihood of accidents as the operator is not looking where he or she is going while changing the temperature setting.
U.S. Pat. No. 2,662,961 issued Dec. 15, 1953 to Sargent disclosed a thermally regulated internally heated steering or control wheel. While Sargent mentions that the device may be used in vehicles in which the steering mechanism is partially or completely exposed to the elements, it is evident from his discussion and the figures that the device is mainly intended to be used with steering wheels enclosed in the cabin of a car and that there is no appreciation of the importance of thermostat location.
U.S. Pat. No. 5,757,165 issued May 26, 1998 to Minks describes a snowmobile handlebar heater control. The system disclosed by Minks monitors the load on the power supply and adjusts power to the heating element based on the total power being supplied. Such a system is primarily concerned with power management with the handlebar heaters being of lesser importance. Thus, the system described by Minks is designed to provide less power to the handlebar heaters when there is a greater power demand from other parts in the system. Furthermore, the thermistor measures ambient temperature rather than the temperature at the interface between the handle bars and the operator's hands. Thus, it can be seen that rider comfort and safety is of secondary importance.
Equipment having exposed rider grips, such as some equipment in the recreational vehicle industry, has become more hi-tech and rider comfort and safety have become increasingly important. There is a continuing need in the art to provide a safe, simple and effective method of controlling heating elements in the grip surfaces of vehicles to increase the comfort of a rider while reducing power consumption.